252 



HEMIPTERA. 



Fig. 95. 



more, till nothing is left but the dry outer convex skin, and 

 the insect perishes on the spot. Sometimes 

 the insect's body is not large enough to cover 

 all her eggs, in which case she beds them 

 in a considerable quantity of the down that 

 issues from the under or hinder part of her 

 body (Fig. 95). There are several broods 

 of some species in the year ; of the bark -louse 

 of the apple-tree at least two are produced 

 in one season. It is probable that the insects 

 of the second or last brood pair in the au- 

 tumn, after which the males die, but the 

 females survive the winter, and lay their 

 eggs in the following spring. 



Young apple-trees, and the extremities of 

 the limbs of older trees, are very much subject to the attacks 

 of a small species of bark-louse. The limbs and smooth 

 parts of the trunks are sometimes completely covered with 

 these insects, and present a very singularly wrinkled and 

 rough appearance from the bodies which are crowded closely 

 together. In the winter these insects are torpid, and ap- 

 parently dead. They measure about one tenth of an inch in 

 length, are of an oblong oval shape, gradually decreasing to 

 a point at one end, and are of a brownish color very near to 

 that of the bark of the tree. These 

 insects resemble in shape one which 

 was described by Reaumur* in 1738, 

 who found it on the elm in France, 

 and Geoffroy named the insect Coc- 

 cus arborum linearis, while Gmelin 

 called it conchiformis (Fig. 96). This, 

 or one much like it, is very abundant 

 upon apple-trees in England, as we 

 learn from Dr. Shaw f and Mr. 



Fig. 96. 



* Memoires, Vol. IV. p. 69, plate 5, figs. 5, 6, 7. 

 t General Zoology, Vol. VI. Part I. p. 196. 



